This invention relates generally to pipe fittings and, more particularly, to fluid-tight and liquid-tight pipe unions which permit two coaxial sections of pipe to be connected and, subsequently, disconnected without rotating the pipe sections.
Long runs of pipe typically require one or more couplings which join individual sections of pipe. The simplest type of coupling is a standard coupling. Larger in diameter than the pipe sections to be joined, the standard coupling is a short piece of pipe internally threaded at both ends. Each threaded end receives an externally threaded end of a pipe section. In order to make the connection, either the pipe section or the standard coupling must be axially rotated. Unions are typically much more costly than standard couplings. The advantage of a union is that the individual pipe sections need not be axially rotated to make the connection. A standard pipe union typically consists of three major components: a flanged first fitting that is internally-threaded to receive the externally threaded end of a first pipe section; an internally threaded collar that slides over the first fitting, the collar having an inwardly-projecting rim at one end that abuts against the flange of the first fitting; and a second fitting that is internally threaded to receive the externally threaded end of a second pipe section, the second fitting also having external threads sized to engage the internal threads of the collar.
A variety of pipe unions have been designed and manufactured over the years. For example, U.S. Pat. No. 4,586,735 to Innes discloses a pipe union having a gasket and retaining/centering device for improved sealing of the joint. U.S. Pat. No. 5,529,284 to Berger, et al. discloses a reusable pipe union that is especially adapted to use over a wide temperature range and which can be repeatedly cycled between extremes of temperatures without the need for retightening. U.S. Pat. No. 4,057,268 to Sicard discloses a disconnectable pipe union designed for robotic assembly at ocean depths beyond those accessible by divers. The union is comprised of two half unions which are secured together with an assembling nut with a toothed ring. Each half union includes a jaw which cooperates with a sliding ring that is displaced by the assembling nut.
The present invention represents an adaptation of an apparatus, having common inventorship, that was originally designed to affix an improved magnetron target to a rotatable support spindle. The improved target includes a circumferential shoulder which includes an extensive circumferential lip which fits over the spindle""s outer mating circumferential edge. The shoulder terminates in a circumferential, inwardly-angled, overhanging step. The target and spindle are coupled together with an generally annular retainer ring having external, outwardly-facing circumferential threads, and a split clamping collar having an inwardly-angled clamping ledge at one end thereof that mates with the overhanging circumferential step on the target, and internal, inwardly-facing circumferential threads at the other end, which mate with the external threads of the retainer ring. The retainer ring is rotated with a spanner wrench so as to engage the threads of the split clamping collar. As the retainer ring engages the rear face of the spindle flange, the clamping collar and retainer ring act in concert to draw the target and spindle together as a unified assembly. An O-ring is employed to maintain a fluid-tight seal between the target and the spindle.
This invention embraces multiple embodiments of a fluid-tight union for reversably interconnecting first and second lengths of coaxial pipe, said union. The union is intended for use with vacuum and pressurized gas lines and pressurized liquid lines. All of the embodiments share the following common elements:
a first annular fitting attachable to a connection end of said first length of pipe, said first fitting incorporating a circumferential flange, said flange having a rear face and front face which faces said second length of pipe;
a second annular fitting attachable to a connection end of said second length of pipe, said second fitting having a circumferential shoulder adjacent a junction with said first fitting, said shoulder terminating in an inwardly-angled, overhanging circumferential step that faces away from said junction;
a clamping collar comprised of arcuate segments, which are collectively sized to generally and coaxially surround both said first and second fittings, said collar incorporating, both an inwardly-angled clamping ledge that engages the overhanging step of the second fitting and at least one internal, inwardly-angled, spiral, circumferential thread spaced apart from said clamping ledge; and
a retainer ring sized so as to be slidable over said first fitting, and rotatable against the rear face of said circumferential flange, said retainer ring incorporating external, spiral, circumferential threads that are angled away from the said flange, the external threads of said retainer ring engaging the internal threads of said clamping collar to draw the clamping ledge and engaged second fitting against the flange as the retainer ring is rotated in a thread engaging direction.
Any of the embodiments may also include a metal seal crushable between the first and second annular fittings. Alternatively, they may include a rubber O-ring seal compressible between the first and second annular fittings. A rubber O-ring seal may be positioned in one of several locations: within a groove on a face of either the first or second annular fittings; within a corner of a cylindrical recess on either the first or second annular fittings, the recess sized to receive a generally cylindrical projection from the other annular fitting, a circumferential edge of which compresses the O-ring about its circumference; or within a groove within a cylindrical recess on either the first or second annular fittings, the recess sized to receive a cylindrical projection from the other annular fitting, the cylindrical surface of which compresses the O-ring about its circumference. A crushable metal seal, on the other hand may be located within a corner of a cylindrical recess, being crushable by the circumferential edge when the two annular fittings are brought together.
Another variation is the manner of attachment of the first and second fittings to the first and second pipe sections. For one embodiment of the invention, each of the fittings is butt-welded to its respective pipe section. For another, each of the fittings is threadably attached to its respective pipe section.
For a preferred embodiment of the invention, the clamping collar is comprised of a pair of generally 180-degree arcuate segments. An additional feature that may be incorporated in any of the embodiments is the hingeable interconnection of the arcuate segments.
The external threads of the retainer ring and the internal threads of the clamping collar may be of either a left-handed or right-handed spiral configuration.
For one embodiment of the invention, provision is made for disconnection of the union without the need for separating the joined pipe sections in a direction along their axes. In order to accomplish this object, an annular collar is provided on either of the annular fittings, which can be slid forward to centerably engage the other fitting. The annular collar may be retracted in order to disengage the two abutting fittings in a sidewise manner.